1. Technical Field
The present application relates to a network system and an information processing method, capable of storing programs dividedly on a plurality of information processing apparatuses connected in a ring form, collecting necessary programs for execution, and executing the programs.
2. Description of the Related Art
With the recent advancement of communication techniques, an expanding range of services including IP telephony service is offered as services provided through general networks. Programs installed in IP communication apparatuses for use in such services are downloaded via a network, for example, the Internet.
FIG. 1 is a block diagram showing the structure of a conventional IP communication system. In the conventional IP communication system, for example, a plurality of IP communication apparatuses 1, 1, . . . are connected to a ring network 2, and an external storage apparatus 3 which is shared by all the IP communication apparatuses 1, 1, . . . is connected within the network 2. Programs to be executed by the respective IP communication apparatuses 1 are stored in the external storage apparatus 3.
Each IP communication apparatus 1 stores a minimum number of programs necessary for activation, and programs necessary for processing are downloaded from the external storage apparatus 3. Each IP communication apparatus 1 extracts a downloaded program into the own memory and executes the program (see, for example, Japanese Patent Application Laid-Open No. 3-98153(1991)).
In the case where the IP communication apparatuses 1, 1, are connected in a ring form, if an error occurs in one IP communication apparatus 1, it causes an error in downloading programs to other IP communication apparatuses 1, 1, . . . . Therefore, for example, by using a fault-tolerant circuit as disclosed in Japanese Patent Application Laid-Open No. 2003-162514, redundancy is provided for errors.
However, in the IP communication system with the structure shown in FIG. 1, since the external storage apparatus 3 for downloading programs is required, it is difficult to simplify the system structure. Moreover, when errors occur on a line connecting the external storage apparatus 3 and the ring network 2, there arises a problem that programs necessary for the IP communication apparatuses 1, 1, . . . can not be downloaded.
Further, even when programs are downloaded into the IP communication apparatuses 1, 1, . . . , if a program to be executed is a large program and there is not a sufficient available memory capacity, it is impossible to extract the downloaded program into the memory. Thus, there are also problems that the downloaded program can not be executed or may cause erroneous operations.